UHP Waterjetting - the Oldest - New Method for Surface Preparation

3 - Surface preparation of component materials

Objective: Repair of an indirect restoration is usually preferred over its replacement. This study aimed to evaluate the effect of silane in different surface preparation techniques on the bond strength of direct to indirect composite resin.Methods: For this in vitro experimental study, 48 indirect composite cubes were fabricated, divided into 4 groups of 12 and subjected to the following preparation techniques: Group 1. Sandblasting with 50μaluminum oxide particles (SB), Group 2. Sandblasting+ silanization (SB+Sil), Group 3. Etching with 9.5% hydrofluoric (HF) acid, Group 4. Etching with 9.5% HF acid+ silanization (HF+Sil). Before the restoration process, specimens were subjected to 500 thermal cycles and received surface preparations. Single Bond adhesive was applied to the surface in all groups. Specimens were restored with direct composite resin and stored in an incubator at 37°C for 24h. Fracture was induced in the specimens by an Instron machine and the shear bond strength was measured. Data were converted to mega Pascal and analyzed using two-way ANOVA and Tukey’s post hoc.Results: The highest shear bond strength was 13.85 (2.75) MPa and belonged to group 1; while the lowest bond strength was 8.43 (1.35) MPa and observed in group 2.Conclusion: Based on the obtained results, composite surface preparation by sandblasting yields more favorable results than HF acid etching and application of silane can also increase the bond strength.

Adhesive bonding is a commonly used technique to join different parts or structures. The bonding is attributed surface adhesion. Adhesion is defined by the ASTM [1] as “the state in which two surfaces are held together by interfacial forces which consist of valence force or interlocking action or both.” Both of these are highly dependent on the surface conditions, which makes the surface preparation very critical to the performance of adhesive bonding. Obtaining a strong adhesive bond requires various considerations. Wegman and Levi [2] describe several key steps of adhesive bonding that are summarized here: receiving materials, knowledge of the fabrication process for the parts, mating the parts to be bonded, and surface preparation. Among all these steps, surface preparation is usually the most critical, complex, and frequently neglected step in the bonding sequence. Surface preparation can remove the intermediate surface, paint, rust or oxide layer. Different materials including adherents, adhesives, and chemicals require different surface preparation techniques but in general, the surface preparation needs to consider the cleanliness, roughness, and functionality of the surface.Adhesive bonding techniques specific to Aluminum and Copper are highlighted.

Investigation on bonding behavior between CFRP patch and corrosion-damaged steel associated with surface preparation techniques

Background:Porcelain from prosthesis such as crown or bridge can be fractured if exposed to trauma; and, can be repaired at chairside using composite resin.Aim:To investigate the fracture resistance of few techniques of surface preparation in repairing fractured porcelain using composite resin.Materials and Methods:Eighty samples of porcelain blocks were divided into 4 groups for different surface preparations, such as, Cimara repairing kit; porcelain etch kit containing hydrofluoric acid; Panavia F resin cement; and, sandblasting using aluminium oxide, before composite resin (Filtek Z250, 3M ESPE) was bonded to the prepared porcelain blocks. Twenty others samples in the control group comprised of pure porcelain blocks. The fracture resistance of each sample was tested using Instron machine (UK).Results:With the exception of the group repaired using hydrofluoric acid (3.04±1.04 Mpa), all the other groups showed significant difference in the fracture resistance values when compared to the control group (3.05 ± 1.42 MPa) at P<0.05.Conclusions:Etching of the porcelain blocks with hydrofluoric acid holds promise in the repair of fractured porcelain with composite resin at chairside.

This article addresses the problems encountered during surface preparation and surface passivation of the InAs-GaSb strain layer superlattice. An analysis of the surface preparation techniques along with the effect on the performance characteristics for different passivants is presented. The passivants and surface preparation techniques are compared on the basis of their insulation properties, capacitance-voltage (C-V) characteristics, minority carrier lifetime, and 1/f flicker noise characteristics.

Surface preparation techniques for biomedical applications

The influence of several surface preparation techniques, such as electropolishing, chemical polishing, anodizing, and firing in an UHV furnace with different cool-down cycles, on Q0 values, peak rf fields, and surface mean free path ls have been studied in a welded S-band cavity having large beam tubes. With special treatments, peak fields up to 810 G at Q0≈1011 have been obtained, whereas the surface mean free paths stayed fairly short (≲300 Å ) not changing systematically with (surface) treatment. Hence, to obtain low rf losses and high rf fields, the purity is not important, but, as we will explain, the spatial homogeneity is very important. Measurements with Nb cylinders, processed like the cavities, showed that the variation of flux penetration depth λ(Hdc) with a dc magnetic field Hdc parallel to the cylinder surface changed markedly with surface treatment. This variation of λ(Hdc) shows several features, which are related to surface properties, namely, the reversibility near Hc1 and the signal at Hc2 as indications for roughness or oxygen in the surface sheath, the irreversibility between Hc1 and Hc2 as an indication for inhomogeneities, especially NbO precipitates, in a Nb surface layer. For example, by this method we observed that the usual cool down from 400 to 50°C in the UHV furnace deteriorates a Nb surface layer of several μ thickness. These surface properties obtained with λ(Hdc) are not only important for achieving better rf cavities but also for ac power transmission lines.

In this work, we investigated experimentally the various factors influencing the extraction of indentation stress-strain curves from spherical nanoindentation on metal samples using two different tip radii. In particular, we focused on the effects of (i) the surface preparation techniques used, (ii) the presence of a surface oxide layer, and (iii) the occurrence of pop-ins at the elastic-plastic transition on our newly developed data analysis methods for extracting reliable indentation stress-strain curves. Rough mechanical polishing was shown to introduce a large scatter in the measured indentation yield strengths, whereas electropolishing or vibropolishing produced consistent results reflective of the pristine sample. The data analysis techniques used were able to discard the portions of the raw data affected by a thin oxide layer, present on most metal surfaces, and yield reasonable indentation stress-strain curves. Experiments with different indenter tip radii on annealed and cold-worked samples indicated that pop-ins are caused by delayed nucleation of dislocations in the sample under the indenter.

The surface preparation technique was used to estimate the sensory cell population and density in the organ of Corti of seven harp seals and four ringed seals. The average total of inner hair cells for the harp seal was 3654 (3078–263) as compared with an average total of 3232 (3120–3354) in the ringed seal. The average total number of outer hair cells in the harp seal was 14 318 (12 173 – 15 709) as compared with an average total of 13 497 (12 903 – 14 894).The distribution of outer and inner hair cells showed an increase in density from base to apex. An increase in density of about 21% and 29% was observed in the inner hair cells of the ringed and harp seal. The increase in density for each row of outer hair cells was 21% in the harp seal and 17% in the ringed seal. The density of outer hair cells per unit surface area decreased from a maximum value at the base to about half its value at the apex.The average total sensory cells of seals exceeded the average total sensory cells of both man and dolphin but were within the range of variation of the human.

Joints are introduced into concrete pavement to control cracking and to allow thermal movements. Sealing of concrete pavement joints to keep incompressibles and water out of the system is critical for the long-term performance of a roadway. Water introduced into the system through the joints can destabilize the slabs and accelerate the degradation of the load transfer rods. Incompressibles introduced into the joints will retard and inhibit the designed movement of the joints. This study assesses the durability of three different sealants placed in assemblies utilizing concrete typical of roadways with various surface preparation methods. Sawed concrete blocks were evaluated with various consolidating primers on concrete. Joint assemblies were fabricated with sealant according to ASTM C719-14 dimensions and subjected to tension movement after immersion in MgCl2 solutions at various temperatures. Visual inspection based on ISO 19862 criteria for adhesion performance was recorded so that surface preparations/treatments could be compared to one another. Controls of joint assemblies immersed in tap water at elevated temperatures showed that MgCl2 had a significant impact on the durability of two of the three sealants tested. This test method of evaluating the adhesion degradation in salt solutions at elevated temperatures proved to be a highly effective method of inducing failures in two of the three sealant materials tested.

In both Asia and Europe, preconstruction primers (PCP) are routinely used and retained as an integral part of the coating system. The retention of PCPs can significantly reduce the painting cost of new ship builds. The cost of protective coatings (paint) application in new construction can be upwards of 10% of the total ship cost. The process is labor intensive; therefore, it is logical that most savings are derived from reducing labor steps. Retaining PCP eliminates the necessity of a second blast operation, thus reducing labor cost and hazardous waste disposal cost. This paper addresses the feasibility of retaining PCP as the permanent primer for protective coatings systems applied in such high-performance areas as exterior hull, underwater bottom, and most importantly ballast tanks. Should the retention of PCP be proven as a viable option, the process of coatings application can be improved resulting in significant cost savings. Spending of new construction dollars will not be necessary to remove the PCP prior to the application of high-performance coating and lining systems. The test program discussed in this paper was based on work sponsored by the National Shipbuilding Research Program Advanced Shipbuilding Enterprise (NSRPAES) and the US Navy. The Surface Preparation and Coatings Panel, SP3, of the Ship Production Committee formulated the program and provided direction during the course of the work. The Ship Production Committee is one of SNAME's nine technical and research committees, and consists of the chairman supported by the ship production major initiative panel chairs and selected others.

Introduction In the past 10 years there has been a radical change in laws governing the oil and gas industry. These changes are due to environmental emphasis and public support. We have been reluctant to change from the regular way of doing things. The nature of the industry is exploration in low-population, inaccessible areas where it was not considered necessary to take adequate precautions. Oil and gas were and still are a low yield for investors; economy is demanded on every front. Ten years ago you were lucky if you received $3.00 a barrel for your oil, and 20 cents a thousand for your gas. The economic squeeze has not been eliminated; inflation has taken its toll; the cost of material, machinery, equipment and personnel, life of well contracts, depletion of the more prolific shallow reserves still does not make oil and gas the most appealing investment available. Many states as well as the national energy policy writes us off as a depleted industry. States, if not by choice, also downgrade our importance by national pressures. The oil and gas industry cannot be written off; we have a very demanding and important part to play in the energy picture during our lifetimes and that of our children. There is no utopian cheap fuel of any kind in history. Drilling and producing smaller wells, deeper wells, and enhanced recovery are expensive. With federal regulations on all energy industry, we will continue to be competitive, and the leader in energy resources. Some of you remember the formation of the Environmental Protection Agency; their first regulations were directed toward Protection Agency; their first regulations were directed toward oil spills. I asked at one meeting, "Why are you directing your efforts toward the oil industry while other, more hazardous and toxic materials are prevalent?" The response was that oil spills could be detected with just a rainbow showing up on the water; therefore, they are the easiest pollutant to detect. The EPA would begin with oil and expand to other areas. The Santa Barbara Channel and the Michigan gas blowout received national attention and had a great influence on the various state and federal laws. In West Virginia a salt-water pollution problem had a significant effect on their laws. pollution problem had a significant effect on their laws. It is interesting to note as you are reading the various state laws the emphasis that is placed on a single accident or problem, and what the state feels is primarily important in that problem, and what the state feels is primarily important in that specific state. It is very apparent that all state laws continually are being upgraded to meet federal demands. An excellent example is the EPA. Their regulations allow a state so much time to upgrade their regulations to meet their minimum requirements, or they will be the regulator. They, along with so many federal agencies, have matching money for an assistance program to aid the states in inventories, policing and reporting. One of the basic requirements is for the state's highest elected official to pledge the state to meet their requirements. In this study we will review the oil and gas laws of Kentucky, Virginia, West Virginia, Pennsylvania, New York, Maryland, Michigan, Ohio, and Tennessee. It is interesting to note in every case that the regulatory agency for oil and gas is a subordinate of some other agency (except Tennessee). REGISTRATION In Kentucky there is no defined process for registration. They do require an affidavit of transfer of ownership, and also require bonding by the new owner. In Virginia all drillers, owners, and operators must register. West Virginia requires all owners to register with the department. In case of a corporation or out-of-state owner, a responsible agent who is a resident must be named, and any change in agents must be reported within 5 days.

Unrecycled tire waste is an enormous global problem because of its non-biodegradability, flammability, and chemical composition. The production and disposal of tires have been on the rise ever since. Due to a shortage of natural resources and increase in waste disposal cost, waste tires in the form of crumbs are widely used as a lightweight material for the backfill in embankment construction. Due to the inherent energy absorption and damping behavior of rubber, research on sand-tire crumb mixtures has shown that there is increase in shear strength and energy absorption capacity. But, very few tests have been performed on soil-tire crumb mixtures. The primary objective of our study involves covering this gap by determining the shear strength and energy absorption characteristics of soil-tire crumb mixture (STCM) by performing direct shear and unconsolidated undrained (UU) triaxial test on disturbed soil samples collected from various site locations, by varying percentage of tire crumbs. Site response studies are done using DEEPSOIL software using both linear and nonlinear methods. Based on the result obtained, it is observed that there is an increase in shear strength in the range of 20–30%, increase in energy absorption 15–20%, and reduction in PGA by 10–15% for the optimum percentage of tire crumb which is site-specific.KeywordsTire crumbsSoilPGAShear strengthEnergy absorption

A new surface preparation and bevelling technique for spreading resistance measurements on N- and P-type silicon : T. F. Unter and D. R. Lamb. Microelectronics6, 17 (1975)